1. Field of the Invention
The present invention relates to an industrial robot apparatus having a plurality of robots, which use a rail in common.
2. Description of the Related Art
An example of conventional industrial robot apparatuses is an apparatus having a plurality of robots which use a rail in common, as disclosed in Japanese Patent Application No. 62-247214.
In such an apparatus, each of the robots is moved by being guided along the rail and is exclusively engaged in a separate working process so that robot works such as processing of a work piece can be performed with high productivity.
In the above conventional industrial robot apparatuses, however, when one robot works, deflection of the rail, which is caused by the movement of another robot, sometimes causes the displacement of the robot which works. Such displacement of the robot, which works, causes a decrease in working precision according to working processes.
It can be also thought that the rail is installed on the ceiling of a factory so that the floor is effectively used. However, it is difficult to increase the rigidity of the rail installed, and the position and state of the robot, which works, are changed by the movement of another robot.
There is thus a problem in that necessary working precision cannot be obtained.